Thys

I can understand why one needs to plug the timing belt cavity and the bell housing cavity when wading, but why must the pluge be removed when not wading?

I used the standard temperature sensor that was supplied with the temperature gauge. The temperature sensor supplied with the Little Black Box EMS IV, includes an adapter that screws into the head. I removed the EMS IV sensor, filled the adapter with coolant, and fitted the temperature gauge's sensor. The temperature stabilizes at 100 ºC I sacrificed the high temperature alarm of the EMS IV, but can see the temperature movement of the head itself. I still have the coolant level monitor and alarm in the expansion tank, but as in my case the coolant got pushed back into the expansion tank, and eventually the head had no water. It then takes a while for the LR temperature sensor to respond, and by then damage is done. I had the system tested this morning for combustion leaks, and no leakage.

Yep, that is a nice repair kit, and it does look much better than the screws and screw caps used on my Discovery. Pity though about the exchange rates and import costs, it would have been a good option.

Going through the cylinder head repair, and finally replacement exersize, I needed to protect my expenses. I installed an external temperature meter, mesuring the cylinder head temperature. I've decided on a normal range of 100ºC +/- 10ºC, based on high way driving at 120 km/h, and peak hour crawling for 25 minutes.

Stephen, My 300 Tdi auto, non EDC model, goes into 4th just over 80 km/h, and changes one down just below 80 km/h, putting foot to the floor, will make her drop two ratios, and she does go past 3500 rpm. I then get scared and release the pedal to expedite the up-shift. In general I do not like to take a diesel, not even a turbo-diesel to the 4000 rpm mark, they just don't like those high revs. Many 300Tdi manual owners (Discovery) are surprised at the actual pulling power my auto has when accelerating, compared to their manuals, I did no mods to the engine, maybe the auto box does have an edge in terms of smoothness and power/torque curve characteristics?

John, On the 300 Tdi auto (4-speed) the front of the bell housing, i.e. the vertical flat side facing the engine, has an oval access cover, bolted down with a no 10 and 13 bolt. Loosen the no 10, and remove the no 13 bolt. Swing the oval access plate away from the no 13 bolt opening. If the engine is at T.D.C., the locking pin will screw into the threaded opening where you removed the no 13 bolt, and you should be able to slide the lock in position. I normally use a small mirror to make sure the recess in the flywheel is lined up center with the no 13 bolt hole. Phil's way, by bolting a locking bar to the damper pully (there is a special tool available) will be the better way, as the locking pin may tend to yield after applying the 80 Nm torque, and then turning the crank shaft damper pulley bolt a further 90º.

Back to my Tdi's head saga. The new head was engineered free of charge, and I fitted the head yesterday. So far no problems, all the funnies, after installing the old head disappeared. I also went to the trouble of buying an analogue temperature gauge, as the Discovery's gauge is a "switching" type, cold to normal and then, a sudden jump to the red zone. The same applies to the "Little Back Box". It will sound an alarm it the temperature exceeds a value, which should tell you to stop and investigate. Based on what happened to me, I've decided to monitor the actual head temperature, not the water, as the measuring points as designed, does not immediately pick up the problem if the water gets pushed into the expansion tank. With an analogue gauge on the head, one can see the temperature rising, telling you alls not well.....

Jim, the Engineering shop who dit the head uses a subbie to do the pressure tests. I will find the details, and PM to you. Someone asked me if one of the sleeves did'd crack. Is this possible with the Tdi's, as I cannot "see" any sleeve cracks?

I was fortunate to loose my wind screen (fortunate = zero access to be paid). The company replacing the wind screen removed the wind screen, and gave me time to drill holes and screw in self tapping screws with washers. These were done at equal spacing, sufficient to make it look like a button padded dash. The screw tops were capped with matt black screw caps. It came out quite nice. The dash top layer was deformed to such extend, that no kit would have been able to "flatten" the dash top again.

Hi Mark, Yes my abortive costs were R 1 200.00c The additional costs for the new head is R 6 700.00c The total final costs for the cylinder head project will be R 15 000.00c In Gauteng I use a specific supplier, CCA. The price difference between them and the stealers amounts to R 4 000.00c, for a new head. Importing from the UK, with the £/R exchange rate, import duties, shipping etc, it is not worth the cost, as the cost saving gets gobbled up by all the importation costs. So, yes, let's all hope this will be the end of my and my Tdi's "head" drama. I did a quick calculation, and based on the purchase price, one year ago, and adding all my expenses to date (new head), I am still within the resale value of my Discovery, but, after this, the scale is going to start moving in the opposite direction, albeit the fact that I have had the use of her for one year.

Short lived was my jubilation on the completion of my head repair and the knock. On Friday evening, driving to a friend's house, the temperature needle suddenly shot to the red zone. I stopped, and found the expansion tank full, and leaking. The diesel was slow to start on Friday morning and afternoon, and I noted excessive smoke while driving. Removed the head for the third time, no traces of leaking on the head surface, or the gasket. Head as as flat as can be, and the top of the block. Re-looked at a small crack between the no 2 cylinder glow plug port and injector port. Got some more advice; this small crack is the cause of the problem, throw the head away, buy a new head. Phoned the Engineering works. They are adamant that they heated the liquid for the pressure test to 120 ºC, then circulated the liquid to heat the head, then raised the pressure to 8 Bar, and the the pressure stayed constant for 15 minutes? I decided to bite the dust, and buy a new head, it is still worth the expense.

I found the knock! On the back of the crankshaft pulley, facing the engine there is a steel cap, protecting the dust seal and pulley shaft entry into the timing belt cavity. When I removed the pulley on my first removal, I dropped the pulley, on the third removal of the pulley I started the engine, and the sharp knocking was gone. Closer inspection revealed a small "dent on the cap side. I tried to press it out, but the cap was now "out-of-round". Re-installed the pulley, sharp knock was back. It was now 03:00 in the early hours of Thursday morning, in utter desperation I cut the dished end with a sheet metal cutter, and bent the cap flat against the pulley, no more knocking. If I have to remove the pulley again, I will replace it. Obviously, to the experts, the clearances between the pulley cap and the cover plate are minute. I am now a very happy Discovery owner again.

Thebiglad, I must agree with you on the poor design statement, some features on the Tdi leaves me totally baffled, especially for an off-road vehicle, but I will not trade her for a TD5, or any other later Discovery. It still is a great vehicle to own and drive, and maintain, even if you battle your backside off in the beginning, but as you get to know the tricks, things return to normal, and again, as I mentioned in an earlier thread, that is the magic of the Forum, it is a bottomless pit of information, suggestions, good humor, and companionship.

Thanks Les, see my new post on the conclusion of my Tdi's head gasket replacement.

Now this is not a April Fool's prank, I started my Disco, and the knock is still there. I utter desperation, I drained the new Caltex Delo 400, thinking that the lubricant may be the cause of the knocking. I replaced the Caltex with Shell Helix Super Diesel.; no change. I took her for a long drive, highway with speeds up to 120 km/h. No problem with acceleration, or power, just this sharp knocking. I replaced the head gasket, water pump, and timing belt front cover. Is it a big end bearing on it's way out? But how, I only worked on the head? At this point in time I've decided to drive her, and see what happens. I will get experts to listen to this high pitch metallic knock.

Thanks Les and Bogmonster. I took the head back to the engineering works this morning, and we noted that the valve seat still had a lot of "meat". We deepened the no 3, 7 & 8 valves. No 8 was the culprit, 3 & 7 were on the limit. It is now 19:33, and I am busy changing the oil, top up with new oil, coolant filling, and then we will see. One advantage of removing the head again, this time it was easier, and re-assembling went like a dream. After the first re-installation, I found the tappet adjusters and nuts very stiff, and stuck. This time I cleaned the lock nuts with a no 3 tap, and the adjusters with a thread cutter, what a pleasure to set the valve clearances after that exercise! I will report back once she is running.

Thanks Jim, that I did, but my problem lies with the serpentine water pump/altenator,PS belt idler/tentioner pulley bearings.

The latest on the blown head gasket. I had the head skimmed, and gave the engineering works the valve head stand down specifications of: Inlet valve: 0,81 - 1.09 mm. Exhaust valve: 0,86 - 1,14 mm. Knowing the engineer personally, and having used his services for all my vehicles, I collected the head, and re-installed, painstakingly going through all the preparations, and torque sequinces...... Guess what, she started and idled like new, but after idling for 3 minutes a faint metallic knock became audible, increasing as the time went on. I nearly lost it, it took one week of my valuable leave, and an extremely patient wife, and now this. I re-checked the valve clearances, the operation of the injectors, but in the end removed the head again, this time not draining the coolant properly, ending up with coolant spillage in the oil system, all my expensive Caltex Delo 400 messed up. I looked at the piston tops, no 4 piston had a faint circular imprint of the exhaust valve. I then measured the valve head stand down of each of the eight valves, all were within the specified range except No's 7 & 8 valves, both exceeded the stand down by 0,02 mm. So, as usual, my desperate questions: 1. Can I compensate for the 0,02 mm stand down by replacing the current 3-hole head gasket with the one with 0 holes? 2. If not, can one try to cut back on the valve seating faces? 3. Or do I bite the dust, and buy a new head? Cheers

Being busy with my Tdi's head repairs, I checked all the rotating components driven by the crankshaft pulley. Great was my surprise to find the main belt idler pulley, mounted in-situ on the timing belt cover, and the main belt tensioner pulley's bearings noisy and with play. My Disco's got 184 000 km on the odo. Is this normal to have these two bearings failing at this distance and age of 12 years?

Les, Thanks for the reply. I bought the Discovery one year ago, and the coolant was OK. However, based on the previous owner's admitance that the Discovery overheated, and was nursed to the nearest town with a LR Dealership, the enjine may have been run on pure untreated water. As replied to Jim, I will replace the coolant after flushing the block, with a 50% concentrate.

Thanks Jim, I made allowance to replace all the coolant, thus also draining the block, and flushing

What attacked my Discovery's water pump? My 300 Tdi blew the head gasket between no 1 and 2 and a water jacket. The coolant mix was as per specification. The thermostat was as clean as new. The pump was in service for about 2 years. It looks like Microbes, but how can they survive with the coolant mix? Can the coolant mix have a high sulpher content as a result of the combustion leak (I use the standard diesel)? Is the pH level messed up as a result of the carbon content in the coolant? Has some one added Bars Leak or some other gunk to try and stop a slow coolant leak? What scares me is that the innards of the cooling jackets inside the block may look the same? Could this condition be the cause of gradual over heating, resulting in the head gasket eventually leaking? Lots of questions, but I am very concerned.

Les, I did some investigation work, and traced the previous owner. I did this because when I removed the head, it was obvious that the head had been removed before. He then admitted that while touring in Namibia, two years ago, the serpent belt broke, resulting in the engine overheating. He nursed the LR back to the nearist town where LR only replaced the head gasket, without checking the head for warping. Looking at the leak, no obvious crack is visible, but a coolant flow path is crearly present from the coolant path, into both no 1 and 2. The head is currently at an engineerig shop for a pressure test. I will have the result on Tuesday morning.

Guys, thanks for all the advice and help with my 300's cooling system. I am in the process of stripping, got stuck when the standard Gedore and Stahlwillie sockets would not fit on the manifold nuts, looks like one requires a "thinner type socket and shaft. What did come up when removing the water pump bolts, was that the bolts were coated in a thick layer of Copper Slip. This indicated to me that the pervious owner had work done on the water pump/cooling system. The first thermstat I removed was also in an immaculate condition for an engine with 184000 km on the odo, maybe the cooling system played up before? Les I am fortunate to have a good friend of mine with his own motor engineering works, he also confirmed the tendancy that the 300's has to develop a cracked head. Will do the the "full Monty" on the head, and replace all the rubber hoses, thermostat, pump, head bolts and manifold studs, bolts. As will be recalled, I replaced the injectors a while ago, so lets see what comes out in the wash. Will do a photo history of the project. Cheers!

I took my Disco to a local radiator shop, they did the combustion leak test, the dark blue liquid started bubbling, and changed colour, head gasket or cracked head. I will stat stripping tonight................................